Scroll compressor

ABSTRACT

The present invention relates to a scroll compressor. The scroll compressor is configured to have a discharge outlet ( 113 ) of a fixed scroll ( 110 ) and a discharge guide groove of an orbiting scroll ( 120 ) for med in non-circular shapes such as a heart shape. Accordingly, it is capable of preventing a refrigerant from being incompletely or excessively compressed without additional bypass valves, thereby being capable of reducing a fabrication cost of the compressor. And, since it is not required to consider interference by other components at the time of installation of a bypass valve, it is capable of simplifying a fabrication process.

TECHNICAL FIELD

The present invention relates to shapes of a discharge outlet and a discharge guide groove in a scroll compressor.

BACKGROUND ART

Generally, a compressor serves to convert mechanical energy into compressive energy of fluid. Compressors may be categorized into a reciprocating type, a rotary type, a vane type and a scroll type according to a compressing mechanism with respect to fluid.

The scroll compressor is provided with a driving motor for generating a driving force and a compression unit for compressing a refrigerant, compressive fluid by receiving the driving force from the driving motor, within a hermetic casing.

The compression unit consists of a fixed scroll fixed at the casing by being provided with a fixed wrap and an orbiting scroll performing an orbiting motion by being provided with an orbiting wrap to be engaged with the fixed wrap. The fixed wrap and the orbiting wrap have the same base circle radius and are formed to have one involute curved line shape from a start angle to an end angle. Further, the fixed wrap and the orbiting wrap are engaged with each other with a phase difference of 180°.

In the scroll compressor, as the orbiting scroll performs the orbiting motion with respect to the fixed scroll under a state that the fixed wrap of the fixed scroll and the orbiting wrap of the orbiting scroll are engaged with each other, one pair of compression chambers is formed. Volume of the compressions chambers is reduced as the compression chambers nave toward a center at a time if orbiting motion of the orbiting scroll, and accordingly the compression chambers consecutively compress the refrigerant and discharge it.

In the scroll compressor, a discharge initiation angle depends on geometric shapes of the fixed wrap and the orbiting wrap. Thus, when a volume ratio between a suction volume and a discharge volume is fixed, a pressure ratio is decided by the fixed volume ratio. Accordingly, in the scroll compressor, when the pressure ratio between a suction pressure and a discharge pressure under an operating condition is equal to a pre-designed pressure ratio of the scroll compressor, a compression loss is minimized. But, when the two pressure ratios are not equal to each other, the loss increases. For example, in case that the operating pressure ratio is set to be higher than the designed pressure ratio, a pressure of gas in the compression chambers does not implement the discharge pressure. Thus, a pressure actually discharged is lower than a pressure needed for loads, which causes a compression incompletion. In this state, when the orbiting wrap reaches the discharge initiation angle, a discharge out is opened and thus the refrigerant in a discharge chamber flows backward into the discharge outlet. On the other hand, in case that the operating pressure ratio is lower than the designed pressure ratio, even though the pressure needed for the load is low, the orbiting wrap does not yet reach the discharge initiation angle at a time that the gas pressure in the compression chambers is equal to the discharge pressure, accordingly the gas is continuously compressed, thereby occurring excessive compression. Thus, in the related art scroll compressor, bypass holes are formed at the compression chambers so that the gas can be discharged through the bypass holes in advance when the pressure of the gas reaches the discharge pressure in the compression process in case that the operating pressure ratio is lower than the designed pressure ratio.

However, such bypass device in the related art scroll compressor should be provided with a plurality of bypass valves so as to open/close the bypass holes, accordingly a material cost and the number of assembly processes may increase, thus a fabrication cost may increase. And, a discharge valve or a vacuum state prevention device may be installed on an upper surface of the fixed scroll in the scroll compressor. In this case, the bypass valves may not be installed at desired positions due to interference by positions of the discharge valve or the vacuum state prevention device.

DISCLOSURE OF INVENTION Technical Problem

Therefore, it is an object of the present invention to provide a scroll compressor which is capable of preventing performance of the compressor from being deteriorated according to an operation capacity without additional bypass valves, by changing shapes of a discharge outlet of a fixed scroll and a discharge guide groove of an orbiting scroll.

Technical Solution

To achieve the object, in accordance with one aspect of the present invention, there is provided a scroll compressor comprising a fixed scroll provided with a spiral shaped fixed wrap and an orbiting scroll provided with an orbiting wrap engaged with the fixed wrap of the fixed scroll and farming compression chambers between the fixed wrap and the orbiting wrap by performing an orbiting notion with respect to the fixed scroll. A discharge outlet is formed at a periphery of a start end of the fixed wrap of the fixed scroll so as to discharge a refrigerant having been compressed in the compression chambers and formed in a non-circular shape.

In accordance with another aspect of the present invention, there is provided a scroll compressor comprising a fixed scroll provided with a spiral shaped fixed wrap and an orbiting scroll provided with an orbiting wrap engaged with the fixed wrap f the fixed scroll and forming compression chambers between the fixed wrap and the orbiting wrap by performing an orbiting motion with respect to the fixed scroll. A discharge outlet is formed at a periphery of a start end of the fixed wrap of the fixed scroll so as to discharge a refrigerant having been compressed in the compression chambers. And, a discharge guide groove having a specific depth is formed at the periphery of a start end of the orbiting wrap of the orbiting scroll so as to guide the refrigerant having been compressed in the compression chambers to the discharge outlet. The discharge outlet and the discharge guide groove are respectively formed in non-circular shapes.

Advantageous Effects

The scroll compressor in accordance with the present invention is configured to have the discharge outlet of the fixed scroll and the discharge guide groove of the orbiting scroll formed in non-circular shapes such as a heart shape, thus it is capable of preventing the discharge pressure of the refrigerant from being incomplete or exceeding under a state that the bypass valves are not additionally installed. Accordingly, it is capable of reducing the fabrication cost of the compressor and simplifying the fabrication process because it is not required to consider the interference by other components at the time of installation of the bypass valve.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross section view showing an exemplary scroll compressor in accordance with the present invention;

FIGS. 2 and 3 are planar views showing a fixed scroll and an orbiting scroll in the scroll compressor according to FIG. 1;

FIG. 4 is a planar view showing that the fixed scroll and the orbiting scroll are coupled to each other in the scroll compressor according to FIG. 1;

FIG. 5 is a planar view showing a discharge outlet in the scroll compressor according to FIGS. 1; and

FIGS. 6 and 7 are planar views showing operating status of the scroll compressor according to FIG. 1 respectively in states of high loads and low loads.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereafter, description will now be given in detail of one embodiment of a scroll compressor according to the present invention with accompanying drawings.

As shown in FIG. 1, the scroll compressor includes a casing 10, a driving motor 20 installed at an upper portion of the casing 10 and generating a rotational force and a compression unit 30 installed at an upper portion of the case 10 and compressing a refrigerant after receiving the rotational force generated from the driving motor 20.

The casing 10 has an inner space in a hermetic state. A suction pipe (SP) is communicated with a middle of a wall surface of the casing 10 so as to suck the refrigerant from a refrigeration cycle apparatus. And, a discharge pipe (DP) is communicated with an upper portion of the wall surface of the casing 10 so as to discharge the refrigerant having been compressed in the compression unit 30 to the refrigeration cycle apparatus. A main frame 11 and a sub frame 12 are respectively fixed at upper and lower portions of the casing 10. And, a high-low pressure separation plate 13 is installed at a middle portion of the casing 10, i.e., between the suction pipe (SP) and the discharge pipe (DP), so as to separate the inner space of the casing 10 into a suction space (S1) and a discharge space (S2).

The driving motor 20 includes a stator 21 fixed on an inner circumferential surface of the casing 10 at a lower side of the compression unit 30, a rotator 22 rotatably installed in the stator 21 and a crank shaft 23 coupled to a center of the rotator 22 and transferring a rotational force of the rotator 22 to the compression unit 30.

The compression unit 30 includes a fixed scroll 110 fixed over the main frame 11 and having a lower surface provided with a fixed wrap 111, an orbiting scroll 120 rotatably put on the main frame 11 and provided with an orbiting wrap 121 so as to form a plurality of compression chambers (P) by being engaged with the fixed wrap 111 of the fixed scroll 110 and an Oldham s ring 130 interposed between the orbiting scroll 120 and the main frame 11 and orbiting the orbiting scroll 120 with preventing a rotation of the orbiting scroll 120.

As shown in FIG. 2, the fixed scroll 110 is formed in a circular shape so that an outer circumferential surface of a plate thereof can be closely adhered to an inner circumferential surface of the casing 10. The fixed wrap 111 is formed at the center of a lower surface of the plate. A suction groove 112 is formed at one side of the lower surface of the plate so that the compression chambers (P) can be communicated with the suction space (Si) of the casing 10. And, a discharge outlet 113 is formed at the center of an upper side of the plate so that a discharge side of the compression chambers (P) can be communicated with the discharge space (S2) of the casing 10.

The fixed wrap 111 is formed in an involute shape having a specific base circle radius. And, the fixed wrap 111 has a height and a thickness configured to be respectively same from a start point to an end point thereof.

The discharge outlet 113 is not formed in a right circular shape, but formed in a heart shape configured to be long in a direction toward the end point from the start end of the fixed wrap on the basis of a formation direction of the fixed wrap 111, as shown in FIG. 2, for example. To this end, as shown in FIG. 5, the discharge outlet 113 may be formed within a range of tangent lines when drawing the tangent lines at two points at which the fixed wrap 111 and the orbiting wrap 121 are tangent to each other right before the fixed wrap 111 and the orbiting wrap 121 are spaced from each other. And, the discharge outlet 113 consists cis a first discharge portion 113 a and a second discharge portion 113 b as shown in FIG. 2. The first discharge portion 113 a and the second discharge portion 113 b are communicated with each other. The first discharge portion 113 a is configured to be located at an inner discharge chamber of the orbiting wrap 121 and the second discharge portion 113 b are configured to be located at an outer compression chamber of a start end of the orbiting wrap 121, at a time that the fixed wrap 111 and the orbiting wrap 121 are spaced from each other.

The orbiting scroll 120 is, as shown in FIG. 3, configured to have the orbiting wrap 121 formed in an involute shape having a specific base circle radius at the upper surface of the plate. The orbiting wrap 121 has a height and a thickness configured to be respectively same from a start point to an end point thereof

And, a discharge guide groove 122 is formed at a central portion of the orbiting scroll 120, that is, a peripheral portion of the start end of the orbiting wrap 121, to be symmetric to the discharge outlet 113 of the fixed scroll 110.

The discharge guide groove 122 is formed to have the same shape with the discharge outlet. For example, the discharge guide groove 122 consists of a first discharge guide portion 122 a and a second discharge guide portion 122 b, and the first discharge guide portion 122 a and the second discharge guide portion 122 b are communicated with each other. The first discharge guide portion 122 a is configured to be located at an inner discharge chamber of the fixed wrap 111 and the second discharge guide portion 122 b are configured to be located at an outer compression chamber of the fixed wrap 111, at a time that the fixed wrap 111 and the orbiting wrap 121 are spaced from each other.

Operations of the scroll compressor in accordance with the present invention will be explained.

When a power is applied to the driving motor 20, the orbiting scroll 120 having received the rotational force from the driving motor 20 performs the orbiting notion over the upper surface of main frame 11 by an eccentric distance by the Oldham's ring 130. While the orbiting scroll 120 performs the orbiting notion, one pair of compression chambers (P) consecutively moving are formed between the fixed wrap 111 of the fixed scroll 110 and the orbiting wrap 121 of the orbiting scroll 120. The compression chambers (P) move toward a center by the continuous orbiting notion of the orbiting scroll 120 and then volume thereof is reduced, thereby compressing the refrigerant sucked through the suction pipe (SP).

Here, the process that the refrigerant is discharged from the compression chambers (P) formed between the fixed scroll 110 and the orbiting scroll 120 will be explained in detail with reference to FIGS. 6 and 7. As shown in FIG. 6, when an operating pressure ratio of the compressor is set to be higher than a designed pressure ratio, as shown in FIG. 6, that is, when the compressor is operated under a state of high loads, a time to initiate discharge should be delayed so as to increase the discharge pressure of the compression chambers to a needed pressure.

However, since the second discharge portion 113 b of the discharge outlet 113 and the second discharge guide portion 122 b of the discharge guide groove 122 in accordance with the present invention are respectively configured to be long toward each upper side, not in the circular shape according to the related art, the discharge outlet 113 may be opened in a state that the pressure of the refrigerant does not reach the needed pressure. And accordingly, the pressure lithe discharge space (S2) of the casing 10 is higher than that of the opened compression chambers (P), thus the refrigerant may flow backward into the compression chambers (P) from the discharge space (S2). However, in the present invention, a front side of the discharge outlet 113 is covered with the thickness of the orbiting wrap 21, accordingly it is capable of preventing the incompletely-compressed refrigerant from being exposed to the discharge outlet 113. Thus, it is capable of preventing the refrigerant in the compression chambers from being incompletely (or, insufficiently) compressed. Also, it is capable of preventing loss of the compressor caused by a channel resistance occurring resulting from that a time to open the discharge outlet 113 is delayed even though a specific amount of refrigerant is previously discharged even in the incompletely-compressed state.

Meanwhile, as shown in FIG. 7, when the operating pressure ratio of the compressor is set to be lower than the designed pressure ratio, that is, when the compressor is operated under a state of low loads, the time to initiate discharge should be early so as to prevent the discharge pressure of the compression chamber from being higher than the needed pressure, thereby preventing the loss of the compressor. In this case, as the discharge 113 of the present invention is configured to be long toward the upper side thereof, comparing with the circular-shaped discharge outlet, the time to initiate discharge for the compression chambers (P) may be early, accordingly it is capable of preventing the discharge pressure of the compression chambers from exceeding the needed pressure without additional bypass valves.

As the pressure of the compression chambers can be modulated according to the loads in a state that the plurality of bypass valves are not installed at the fixed scroll, it is capable of preventing increase of a fabrication cost caused by installation of the bypass valves and of preventing interference by other components.

The scroll compressor in accordance with the present invention is configured to have the discharge outlet of the fixed scroll and the discharge guide groove of the orbiting scroll formed in non-circular shapes such as a heart shape, thus it is capable of preventing the discharge pressure of the refrigerant from being incomplete or exceeding under a state that the bypass valves are not additionally installed. Accordingly, it is capable of reducing the fabrication cost of the compressor and simplifying the fabrication process because it is not required to consider the interference by other components at the time of installation of the bypass valve.

It will also be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

INDUSTRIAL APPLICABILITY

The scroll compressor in accordance with the present invention can be applied to a refrigeration device using a refrigeration cycle apparatus such as a refrigerator, as well as an air conditioner.

Sequence Listing

scroll, discharge outlet, bypass valves, incomplete compression, excessive compression 

1. A scroll compressor comprising: a fixed scroll provided with a spiral shaped fixed wrap; and an orbiting scroll provided with an orbiting wrap engaged with the fixed wrap of the fixed scroll and forming compression chambers between the fixed wrap and the orbiting wrap by performing an orbiting motion with respect to the fixed scroll, wherein a discharge outlet is formed at a periphery of a start end of the fixed wrap of the fixed scroll so as to discharge a refrigerant having been compressed in the compression chambers and formed in a non-circular shape.
 2. The scroll compressor of claim 1, wherein the discharge outlet is configured to be communicated with an outer compression chamber of a start end of the orbiting wrap before the fixed wrap and the orbiting wrap are spaced from each other.
 3. The scroll compressor of claim 2, wherein the discharge outlet comprises a first discharge portion and a second discharge portion communicated with each other, and wherein the first discharge portion is located at an inner discharge chamber of the orbiting wrap and the second discharge portion is formed at the outer compression chamber of the orbiting wrap when the fixed wrap and the orbiting wrap are spaced from each other.
 4. The scroll compressor of claim 1, wherein the discharge outlet is formed to be long in a direction toward the end point from the start point of the fixed wrap on the basis of a formation direction of the fixed wrap.
 5. The scroll compressor of claim 1, wherein the discharge outlet is formed within a range of tangent lines when drawing the tangent lines at two points at which the fixed wrap and the orbiting wrap are tangent to each other right before the fixed wrap and the orbiting wrap are spaced from each other.
 6. The scroll compressor of claim 1, wherein the discharge outlet is approximately formed in a heart shape in a planar projection.
 7. A scroll compressor comprising: a fixed scroll provided with a spiral shaped fixed wrap; and an orbiting scroll provided with an orbiting wrap engaged with the fixed wrap of the fixed scroll and forming compression chambers between the fixed wrap and the orbiting wrap by performing an orbiting motion with respect to the fixed scroll, wherein a discharge outlet is formed at a periphery of a start end of the fixed wrap of the fixed scroll so as to discharge a refrigerant having been compressed in the compression chambers, wherein a discharge guide groove having a specific depth is formed at the periphery of a start end of the orbiting wrap of the orbiting scroll so as to guide the refrigerant having been compressed in the compression chambers to the discharge outlet, and wherein the discharge outlet and the discharge guide groove are respectively formed in non-circular shapes.
 8. The scroll compressor of claim 5, wherein the discharge outlet and the discharge guide groove are configured to be symmetric to each other on the basis of a moving path of the compression chambers in a planar projection.
 9. The scroll compressor of claim 5, wherein the discharge outlet and the discharge guide groove are respectively configured to be communicated with an outer compression chamber of each start end of the fixed wrap and the orbiting wrap when the fixed wrap and the orbiting wrap start to be spaced from each other.
 10. The scroll compressor of claim 9, wherein the discharge outlet comprises a first discharge portion and a second discharge portion communicated with each other and the discharge guide groove comprises a first discharge guide portion and a second discharge guide portion communicated with each other, and wherein the first discharge portion and the first discharge guide portion are respectively located at the inner discharge chamber of the orbiting wrap and the fixed wrap when the fixed wrap and the orbiting wrap are spaced from each other, while the second discharge portion and the second discharge guide portion are respectively located at the outer compression chambers of the fixed wrap and the orbiting wrap when the fixed wrap and the orbiting wrap are spaced from each other.
 11. The scroll compressor of claim 10, wherein the second discharge portion and the second discharge guide portion are formed in an opposite direction.
 12. The scroll compressor of claim 5, wherein the discharge outlet is formed within a range of tangent lines when drawing the tangent lines at two points at which the fixed wrap and the orbiting wrap are tangent to each other right before the fixed wrap and the orbiting wrap are spaced from each other.
 13. The scroll compressor of claim 5, wherein the discharge outlet and the discharge guide groove are approximately formed in heart shapes in a planar projection. 